1. Field of the Invention
The present invention relates to a device for mounting a semiconductor package, especially relates to a device in which a package including a semiconductor element for power amplifying is mounted on a high frequency amplifier device having a microwave band.
2. Description of the Related Art
According to such a trend of large capacity communication as satellite communication in recent years, a demand for power amplifying semiconductor elements providing a high output power is increasing. At present, the output power of higher than 100 W is required in Ku band (12 to 15 GHz) application, and that of higher than 500 W is required in C band (4 to 8 GHz). However, it is important how to dissipate the heat generated by the power amplifying semiconductor elements more efficiently, when higher output power is aimed. This trend of high output power is ever increasing; therefore, heat dissipation of the semiconductor device is an important problem to be solved.
A conventional mounting device is shown in FIG. 1. A package 41 for the power amplifying semiconductor element is mounted on a base board of a system housing 42, in which water-cooling or air-cooling system is built-in, together with other electronic components 43, and heat is dissipated in an integrated form. Because heat dissipation from the power amplifying semiconductor elements is increasing as mentioned above, surrounding electronic components are exposed to high temperature, resulting in an adverse affect on characteristics of electronic components mounted in the surroundings. A problem associated with the conventional mounting method is that there is no design flexibility for the heat dissipation, because a heat dissipation plane of the package for the power amplifying semiconductor element is integrated with the system housing. Therefore, there is a demand to employ a mounting device which can cool power semiconductors independently from system housing.
As an example in which a semiconductor chips are not cooled separately and on a surface of a housing, there is a mounting device, in which a cooling fin is directly made contact with a semiconductor chip, or a semiconductor chip is die-bonded on a metal base by a spring force via heat conducting elastomer or heat conducting grease. This can be seen in a heat dissipation structure of a CPU chip or patent documents (refer to Japanese Unexamined Patent Application Publication No. H7-94912).
However, the semiconductor devices to which these kind of mounting techniques are applicable are those having a package of FC-PGA (Flip Chip Pin Grid Array) type or BGA (Ball Grid Array) type, which is unable to be cooled from the grid array surface. With respect to the mounting for high frequency power amplifying semiconductor elements outputting high power, the problem is unsolved.